Fastener

ABSTRACT

A fastener includes an elongate fastener body defining a longitudinal axis substantially central thereto. The fastener body has a continuous outer fastener shell laterally surrounding the longitudinal axis. The fastener shell longitudinally separates a fastener head end and a fastener tip end. A tool-engaging feature is provided on the fastener head end. A plurality of teeth are located on the fastener shell and extend substantially laterally outward from the longitudinally axis. The fastener shell is comprised of at least one undulate face and at least one substantially flat face. The plurality of teeth are located only on the undulate faces. Each tooth is longitudinally separated from adjacent teeth along an undulate face. A method of installing the fastener into a receiving structure is also described.

RELATED APPLICATION

This application claims priority from U.S. Provisional Application No.61/748,788, filed 4 Jan. 2013, the subject matter of which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to an apparatus and method for use of afastener and, more particularly, to a fastener and method of installinga fastener into a receiving structure.

BACKGROUND OF THE INVENTION

Ligaments are tough bands of tissue which serve to connect the articularextremities of bones, or to support or retain organs in place within thebody. Ligaments are typically composed of coarse bundles of dense whitefibrous tissue which are disposed in a parallel or closely interlacedmanner, with the fibrous tissue being pliant and flexible, but notsignificantly extensible.

In many cases, ligaments are torn or ruptured as a result of accidents.As a result, various procedures have been developed to repair or replacesuch damaged ligaments.

For example, in the human knee, the anterior and posterior cruciateligaments (“ACL” and “PCL”) extend between the top end of the tibia andthe bottom end of the femur. The ACL and PCL cooperate, together withother ligaments and soft tissue, to provide both static and dynamicstability to the knee. Often, the ACL is ruptured or torn as a resultof, for example, a sports-related injury. Consequently, various surgicalprocedures have been developed for reconstructing the ACL so as torestore normal function to the knee.

In many instances, the ACL may be reconstructed by replacing theruptured ACL with a graft ligament. More particularly, with suchprocedures, bone tunnels are typically formed in the top end of thetibia and the bottom end of the femur, with one end of the graftligament being positioned in the femoral tunnel and the other end of thegraft ligament being positioned in the tibial tunnel. The two ends ofthe graft ligament are anchored in place so that the graft ligamentextends between the femur and the tibia in substantially the same way,and with substantially the same function, as the original ACL. Thisgraft ligament then cooperates with the surrounding anatomicalstructures so as to restore normal function to the knee.

In some circumstances the graft ligament may be a ligament or tendonwhich is harvested from elsewhere in the patient; in other circumstancesthe graft ligament may be a synthetic device. For the purposes of thepresent invention, all of the foregoing can be collectively referred toas a “graft ligament”. A “bone graft”, made of a denser/firmer materialthan the relatively soft-tissue graft ligament, may be provided at oneor both ends of the graft ligament to assist with anchoring the graftligament. When present, the bone graft, optionally along with a portionof the graft ligament, may be inserted into a bone tunnel previouslymachined into the tibia or femur, to assist with secure anchoring of thegraft ligament.

SUMMARY OF THE INVENTION

In an embodiment of the present invention, a fastener is described. Anelongate fastener body defines a longitudinal axis substantially centralthereto. The fastener body has a continuous outer fastener shelllaterally surrounding the longitudinal axis. The fastener shelllongitudinally separates a fastener head end and a fastener tip end. Atool-engaging feature is provided on the fastener head end. A pluralityof teeth are located on the fastener shell and extend substantiallylaterally outward from the longitudinally axis. The fastener shell iscomprised of at least one undulate face and at least one substantiallyflat face. The plurality of teeth are located only on the undulatefaces. Each tooth is longitudinally separated from adjacent teeth alongan undulate face.

In an embodiment of the present invention, a method of installing afastener into a receiving structure is described. A fastener isprovided. The fastener includes an elongate fastener body, havinglongitudinally spaced fastener head and fastener tip ends. The fastenerbody defines a longitudinal axis. Two elongate flat faces are provided,each flat face extending substantially parallel to, and laterally spacedfrom, the longitudinal axis. The two flat faces are located laterallyopposite one another on the fastener body. Two elongate undulate facesare provided, each undulate face having a plurality of longitudinallyspaced teeth arranged thereupon. Each undulate face extendssubstantially parallel to, and is laterally spaced from, thelongitudinal axis. The two undulate faces are located laterally oppositeone another on the fastener body. The two undulate faces are laterallyseparated from one another by interposed flat faces. A fastenerperimeter is defined in a lateral plane by the two flat faces and thetwo undulate faces. The fastener perimeter entirely laterally surroundsthe longitudinal axis. A longitudinally oriented receiving aperture isprovided in the receiving structure. The fastener tip end is insertedinto the receiving aperture. The receiving aperture is penetrated withthe fastener body to a predetermined depth. The fastener is maintainedin the receiving aperture in a first alignment. The fastener is rotatedabout the longitudinal axis within the receiving aperture into a secondalignment. At least one tooth is driven laterally into the receivingstructure from the receiving aperture due to rotation of the fastenerinto the second alignment. With the at least one tooth driven laterallyinto the substrate, the fastener is maintained in the receiving aperturein the second alignment to resist longitudinal movement of the fastenerwith respect to the receiving aperture.

In an embodiment of the present invention, a fastener is described. Anelongate fastener body has longitudinally spaced fastener head andfastener tip ends. The fastener body defines a longitudinal axis. Twoelongate flat faces are provided, each flat face extending substantiallyparallel to, and laterally spaced from, the longitudinal axis. The twoflat faces are located laterally opposite one another on the fastenerbody. Two elongate undulate faces are provided. Each undulate face has aplurality of longitudinally spaced teeth arranged thereupon, eachundulate face extending substantially parallel to, and laterally spacedfrom, the longitudinal axis, the two undulate faces being locatedlaterally opposite one another on the fastener body, and the twoundulate faces being laterally separated from one another by interposedflat faces;

-   -   wherein a fastener perimeter is defined in a lateral plane by        the two flat faces and the two undulate faces, the fastener        perimeter entirely laterally surrounding the longitudinal axis.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, reference may be made tothe accompanying drawings, in which:

FIG. 1 is a perspective front view of an embodiment of the presentinvention;

FIG. 2 is a top view of the embodiment of FIG. 1;

FIG. 3 is a front view of the embodiment of FIG. 1;

FIG. 4 is a side view of the embodiment of FIG. 1;

FIGS. 5A, 5B, and 5C are front views of alternate configurations of theembodiment of FIG. 1;

FIG. 6A is a perspective front view of an alternate configuration of theembodiment of FIG. 1;

FIG. 6B is a top view of the embodiment of FIG. 6A;

FIG. 7A is a top view of an example use environment for the presentinvention;

FIG. 7B is a cross-sectional view taken along line 7B-7B of FIG. 7A;

FIG. 8 is an exploded front perspective view of a tool which can be usedwith the use environment of FIG. 7A;

FIG. 9A is a top view of the tool of FIG. 8 in the use environment ofFIG. 7A;

FIG. 9B is a cross-sectional view taken along line 9B-9B of FIG. 9A;

FIG. 10A is a top view of the tool of FIG. 8 in the use environment ofFIG. 7A;

FIGS. 10B and 10C are cross-sectional views taken along line 10B,C-10B,C of FIG. 10A and depicting a sequence of use of the tool of FIG. 8;

FIGS. 11A, 12A, 14A, and 15A are top views of the use environment ofFIG. 7A depicting a sequence of operation of the embodiment of FIG. 1;

FIG. 13A is a top view of the use environment of FIG. 7A depicting analternate step of the sequence of operation of the embodiment of FIG. 1;

FIGS. 11B, 12B, 13B, 14B, and 15B are cross-sectional views taken,respectively, along line 11B-11B of FIG. 11A, 12B-12B of FIG. 12A,13B-13B of FIGS. 13A, 14B-14B of FIG. 14A, and 15B-15B of FIG. 15A;

FIG. 16 is a front view of the embodiment of FIG. 1 in an alternateconfiguration;

FIG. 17 is a side view of the embodiment of FIG. 1 in the alternateconfiguration of FIG. 16;

FIGS. 18A, 19A, and 20A are top views of an example use environmentdepicting a sequence of operation of the embodiment of FIG. 1 in thealternate configuration of FIG. 16;

FIGS. 18B, 19B, 20B, and 20C are cross-sectional views taken,respectively, along line 18B-18B of FIG. 18A, 19B-19B of FIG. 12A,20B-20B of FIG. 20A, and 20C-20C of FIG. 20A;

FIG. 21 is a front view of the embodiment of FIG. 1 in an alternateconfiguration;

FIG. 22 is a side view of the embodiment of FIG. 1 in the alternateconfiguration of FIG. 21;

FIGS. 23A-23B depict a sequence of operation of the embodiment of FIG. 1in an alternate configuration; and

FIG. 23C is a cross-sectional view taken along line 23C-23C of FIG. 23A.

DESCRIPTION OF EMBODIMENTS

In accordance with the present invention, FIGS. 1 and 2 depict afastener 100. The fastener 100 includes an elongate fastener body 102defining a longitudinal axis 104 substantially central thereto. Thefastener body 102 has a continuous outer fastener shell 106 whichlaterally surrounds the longitudinal axis 104. A “lateral” direction108, as described herein, is substantially located within or along alateral plane which is substantially perpendicular to the longitudinalaxis 104 (not restricted to the four arrowed “lateral” directions shownas examples in the Figures). The term “laterally surrounds” is used toindicate that a cross-sectional “slice” of the fastener shell 106 takenwithin a selected lateral plane completely encircles or encloses theportion of the longitudinal axis 104 located within that selectedlateral plane.

The fastener shell 106 longitudinally separates a fastener head end 110and a fastener tip end 112. The fastener head end 110 may include atool-engaging feature 114, as will be discussed in more detail below.The fastener tip end 112 may be relatively tapered (i.e., have a smallerlateral cross-sectional footprint than the corresponding lateralcross-sectional footprint of a portion of the fastener body 102 closerto the fastener head end 110), even to a degree of taper to a relativelysharp point much like that of a commonly available wood screw. Whentapered, the relatively smaller-diameter fastener tip end 112 may assistwith orientation and/or location of the fastener 100 with respect to anexisting receiving aperture and/or with a “self-tapping” function into aface of a substrate without a provided receiving aperture or with only asmall “pilot hole” aperture.

A plurality of teeth 116 are located on the fastener shell 106 andextend substantially laterally outward from the longitudinal axis 104,though this lateral extension contemplates that one or more of the teeth116 may be slightly tilted or canted with respect to a truly lateralorientation. Each of the teeth 116 may be of any desired construction,configuration, frequency, spacing, or have any other desired physicalproperty, without regard to a corresponding physical property of otherteeth of the fastener 100, and various contemplated options for theteeth will be discussed below in more detail. In the Figures, only asingle tooth 116 or a small number of the total teeth 116 depicted maybe called out with element numbers, for clarity of depiction, but one ofordinary skill in the art will understand that similar teeth would benumbered similarly.

The fastener shell 106 may be comprised of at least one undulate face118 and at least one substantially flat face 120, as shown in FIG. 1.The “undulate” or “flat” nature of the face 118 or 120, respectively,may be determined by viewing it laterally (i.e., looking toward thelongitudinal axis, as in the orientation of FIGS. 3-4). An “undulate”face 118 is one that has a wavy, crenellated, dentate, or otherirregular surface, as opposed to a “flat” face 120, which issubstantially planar but may include some incidental irregularities,such as the tooth 116 notches shown in FIG. 2. Stated differently, across-section of an undulate face 118 (e.g., a cross-section taken alonga plane parallel to the longitudinal axis 104, such as along line x-x inFIG. 2) will include at least one peak and/or valley irregularity ordeparture from a base level. For example, FIG. 3 shows a side view ofthe fastener 100 with a profile 322 of one of the undulate faces 118emphasized in heavy line. The undulate face 118 is shown straight-on inthe side view of the fastener 100 in FIG. 4, with the peaks of theprofile 322 extending out of the plane of the page toward the viewer, inthat orientation.

Another way that the fastener 100 of FIGS. 1-2 can be characterized isas including at least two elongate flat faces 120, each extendingsubstantially parallel to, and spaced laterally apart from, thelongitudinal axis 104. The two flat faces 120 are located substantiallylaterally opposite one another on the fastener body 102. In theorientation of FIG. 2, the flat faces are toward the top and bottom ofthe page. Two elongate undulate faces 118 are provided, with eachundulate face extending substantially parallel to, and laterally spacedfrom, the longitudinal axis 104. The two undulate faces 118 are locatedlaterally opposite one another on the fastener body 102. The twoundulate faces 118, which are located toward the left and right of thepage in the orientation of FIG. 2, are laterally separated from oneanother by at least one interposed flat face 120, as shown. A fastenerperimeter 224, shown in heavy line in FIG. 2, is defined in a lateralplane by the two flat faces 120 and two undulate faces 118. The fastenerperimeter 224 entirely laterally surrounds the longitudinal axis 104.

In the embodiment shown in FIGS. 3 and 4, the profile 322 has aplurality of fairly sharp and regularly spaced “peaks” defined by theteeth 116. The plurality of teeth 116 are located only on the undulatefaces 118. Each tooth 116 is longitudinally separated fromlongitudinally adjacent teeth along its respective undulate face 118. Asshown in FIG. 4, each of the teeth 116 extends substantially across alateral width (left to right in FIG. 4) of the undulate face 118.However, it is also contemplated that one or more teeth 116 could belocated across only a portion of the lateral width of the undulate face118, and that any such partial-width teeth (not shown) may be located atany desired location along the length or width of the undulate face 118,without regard to the location or configuration of other partial-widthteeth that may be present.

FIGS. 5A, 5B, and 5C each depict examples of configurations of undulatefaces 118 that could be used with the present invention. In each ofthese Figures, the leftmost undulate face 118 is similar to those ofFIGS. 3-4. In FIG. 5A, the rightmost undulate face 118 a has a pluralityof teeth 116 a which have a similar configuration to, but differentlongitudinal spacing as, the teeth 116 on the leftmost undulate face118. In FIG. 5B, the rightmost undulate face 118 b has a plurality ofteeth 116 b which have similar longitudinal spacing to, but differentconfiguration as, the teeth 116 on the leftmost undulate face 118 b—theleftmost teeth 116 b are significantly shorter than the rightmost teeth116 in this embodiment. In FIG. 5C, the teeth 116 c of the rightmostundulate face 118 c are both fewer in number and smaller in “height”than the teeth 116 of the leftmost undulate face 116, with the teeth 116c also having relatively gentle, wavelike transitions along thelongitudinal length of the rightmost undulate face 116. One of ordinaryskill in the art can readily provide any number and configuration ofsuitable teeth 116, arranged along the undulate face(s) 118 in anydesired manner, for a particular application of the present invention.

With reference back to FIG. 2, each tooth 116 of a selected undulateface 118 may include a leading edge apex 226 defined by a concavefeature (here, the “check mark” shaped portions of the fastenerperimeter 224) in a laterally oriented profile of the selected undulateface 118. The leading edge apex 226, when present, may cause thecorresponding tooth 116 to be asymmetrical along the laterally orientedprofile. In FIGS. 1 and 2, the leading edge apices 226 cause the teeth116 of each undulate face 118 to be asymmetrical with respect to theline x-x. That is, when mirrored top-to-bottom along line x-x, the teeth116 shown in FIGS. 1 and 2 are not symmetrical. When present, theleading edge apices 226 may be located on a portion of selected undulateface 118 (i.e., a “leading edge”) that leads engagement of the tooth 116with an ambient material when the fastener 100 is being rotated aboutthe longitudinal axis 104.

In contrast, and with reference to FIGS. 6A and 6B, when a leading edgeapex 226 is present, it is also contemplated that each tooth 116 of asecond undulate face 118′, other than the selected undulate face 118, issymmetrical along a laterally oriented profile of the second undulateface 118′. That is, while the teeth 116 of the leftmost undulate face118 (in the orientation of FIG. 6B) include leading edge apices 226 tohelp with penetrating the teeth 116 laterally into an adjacent material,the teeth 116′ of the rightmost undulate face 118′ have no leading edgeapices and therefore present a “blunter” surface to the ambientmaterial. This may be desirable, for example, to avoid cutting into theambient material with both undulate faces 118.

An example sequence of operation of the fastener 100 is shownpictorially in FIGS. 7A-15B. In FIGS. 7A and 7B, a longitudinallyoriented pilot hole 728 is provided in a receiving substrate orreceiving structure 730. The pilot hole 728 may be, for example, drilledinto the receiving structure 730 or otherwise formed in any suitablemanner. The receiving structure 730 may be of any suitable type andprovided for any desired reason, though in the interest of discussion,the receiving structure is presumed to be a relatively hard andinflexible patient tissue, such as the bone tissue of a tibia or femurin an ACL replacement surgical setting.

In order for the receiving structure 730 to accommodate the fastener 100as described herein, the pilot hole 728 must be transformed into areceiving aperture. An example of a suitable shaping tool 832 forrefining and adjusting a substantially cylindrical pilot hole 728 isshown in FIG. 8. As can be seen in the exploded view of FIG. 8, theshaping tool 832 includes an elongate guiding rod 834 having a “female”dovetail-shaped guiding track 836. A guided chisel 838 includes a “male”dovetail-shaped guided rail 840 configured for mating engagement withthe guiding track 836. The guided chisel 838 includes a shaping face 842of any desired size, configuration, and sharpness.

The term “mate” is used herein to indicate a relationship between twoseparate structures which are joined or fitted together closely becausethey have similar three-dimensional shapes (e.g., a positive and anegative version of the same contour, respectively). Two structures in a“mated” relationship may include at least some space therebetween, ormay even have a thin interposed structure (e.g., a cushion or membrane),but should be configured to fit substantially closely together at themated interface. The guiding rod 834 may be mated with at least aportion of the guided chisel 838, or these structures may be spacedapart in any desired manner, and by any desired amount.

In FIGS. 9A and 9B, the guiding rod 834 has been at least partiallyinserted longitudinally into the cylindrical pilot hole 728, with theguiding track 836 facing a desired, and possibly predetermined,direction (toward the right of the page, in the orientation of FIGS. 9Aand 9B). In FIGS. 10A and 10B, the guided chisel 838 has been mated withthe guiding rod 836 by insertion of at least a portion of the guidedrail 840 into the guiding track 836. This mating can occur before,during, or after insertion of the guiding rod 834 into the pilot hole728. The shaping face 842 comes into contact with, and optionallypenetrates, the rightmost side (in the orientation of these Figures) ofan interior wall 1044 of the pilot hole 728.

In the sequence of operation from FIG. 10B to FIG. 10C, the guiding rod834 is maintained substantially in the same position within the pilothole 728 while the guided chisel 838 is guided into the mass of thereceiving structure 730 laterally adjacent to the pilot hole 728 throughsliding engagement between the guiding track 836 of the guiding rod andthe guided rail 840 of the guided chisel. It is likely that, for mostapplications of the present invention, a substantial degree of force(above a mere gravitational force upon the guided chisel 838) will beexerted upon one or both of the guiding rod 834 and the guided chisel tocause the motion shown from FIG. 10B to FIG. 10C.

As the guided chisel 838 travels longitudinally downward (in theorientation of FIGS. 10B and 100) into the pilot hole 728, the shapingface 842 comes into penetrating contact with the interior wall 1044 ofthe pilot hole. Due at least partially to this penetrating contact andlongitudinal motion, the shaping face 842 excavates the receivingstructure 730 laterally adjacent to the pilot hole 728. “Excavate” hereis intended to mean “create a cavity or hole in”. This excavation mayhappen via cutting, digging out, or compression of the material makingup the receiving structure 730, any other suitable material removaland/or rearrangement techniques, or any combination thereof. In someembodiments of the present invention, a relief channel (not shown) maybe provided in the shaping tool 832 to facilitate removal from the pilothole 728 of kerf or other loose material created/encountered duringexcavation of the receiving structure 730 laterally adjacent to thepilot hole.

Once the shaping tool 832 has been used as desired, the shaping tool maybe removed from the receiving structure 730. As shown in FIGS. 11A and11B, the shaping tool 832 is used to create, from the pilot hole 728, areceiving aperture 1146 which is rotationally asymmetrical and has astructure-receiving portion 1148 laterally adjacent to afastener-receiving portion 1150.

With reference to FIGS. 12A and 12B, the fastener tip end 112 may beinserted into the receiving aperture 1146, such as into afastener-receiving portion 1150 thereof. The fastener 100 the canpenetrate into the receiving aperture 1146 to a predetermined depth.Optionally, the fastener 100 may include a depth-stop feature (notshown), such as an increased-lateral-width fastener head end, which canbe used to prevent insertion of the fastener deeper into the receivingaperture 1146 than desired.

As shown in heavy line in FIG. 11A, the fastener-receiving portion 1150of the fastener aperture 1146 may have a laterally-oriented footprint1152 which surrounds a majority of the fastener perimeter 224. For manyuse environments of the present invention, it will be desirable to haveat least some, if not all, of the undulate faces 118 of the fastener 100surrounded by the fastener-receiving portion 1150 of the fasteneraperture 1146, such that a flat face 120 of the fastener 100 is exposedor presented to the structure-receiving portion 1148 of the receivingaperture when the fastener is in a first alignment, as shown in FIGS.12A and 12B.

Regardless of the position or exposure of the fastener 100, however, thefastener may be retained in the receiving aperture 1146 in the firstalignment while, as shown in FIGS. 13A and 13B, an anchored structure1354 is at least partially inserted into the receiving aperture,laterally adjacent to the fastener. In the ACL replacement being used asan example herein, the anchored structure 1354 is a relatively rigidbone block 1356 (dimensioned for insertion into the receiving aperture1146) which is attached to a relatively soft/flexible graft ligament1358. The graft ligament 1258 may have a first graft end 1360 which isdirectly connected to the bone block 1356 and a second graft end (notshown) which also may be connected to a respective bone block (notshown) for anchoring elsewhere during the ACL replacement, optionallythrough the use of a second receiving aperture and a second fastener(not shown).

As another option for achieving the physical arrangement of structuresshown in FIGS. 13A and 13B, the anchored structure 1354 could beinserted into the structure-receiving portion 1148 of the receivingaperture 1146 before the fastener 100 is inserted into thefastener-receiving portion 1150 of the receiving aperture.

Regardless of how the receiving structure 730, anchored structure 1354,and fastener 100 achieve their relative positions in the “ready to use”arrangement of FIGS. 13A, and 13B with the fastener in the firstalignment, the fastener 100 may be manipulated by a user at any desiredtime and in any desired manner to rotate substantially about thelongitudinal axis 104 as shown by rotation arrows 1362 of FIG. 13A,which is clockwise, in the orientation of FIG. 13A.

Through rotation of the fastener 100, the arrangement shown in FIGS. 15Aand 15B may be achieved, wherein the fastener is in a second alignment.Here, the fastener has been rotated substantially ninety degrees aboutthe longitudinal axis 104 within the receiving aperture 1146, into thesecond alignment. Due to rotation of the fastener 100 into the secondalignment, at least one tooth 116 has been driven laterally into thereceiving structure 730 from the receiving aperture 1146 (in otherwords, into the rightmost portion of the receiving structure 730, in theorientation of FIG. 15B). Also due to rotation of the fastener 100 intothe second alignment, at least one tooth 116 has been driven laterallyinto the anchored structure 1354 (in other words, into the rightmostportion of the bone block 1356, in the orientation of FIG. 15B)—whichmay have occurred concurrently with driving of the teeth laterally intothe receiving structure 730. The teeth 116 driven laterally into thereceiving structure 730 are arranged upon (associated with) a differentundulate face 118 of the fastener 100 from the teeth 116 drivenlaterally into the anchored structure 1354.

When the fastener 100 is in the second alignment, as shown in FIGS.15A-15B, the user may wish to have a different arrangement of teeth 116upon the fastener shell 106 than that shown. For example, it may bedesirable to have different—or no—teeth 116 that are laterally driveninto a graft ligament 1358 portion of the anchored structure 1354,particularly if the graft ligament portion is more sensitive to damagefrom laterally-oriented tooth contact than is the bone block 1356portion. With reference back to the example tooth configurations ofFIGS. 3-6B, one of ordinary skill in the art could provide a fastenerfor a particular use environment having a plurality of teeth 116 withany desired configuration, shape, size, cross-sectional profile,thickness, material, or other physical property, and the provided teethneed not match each or any other tooth in any respect.

Regardless of how the fastener 100 is moved from the “insertion” firstalignment to the “gripping” second alignment, the fastener may bemaintained within the receiving aperture 1146 via at least one tooth116—of any desired type or configuration—driven laterally into at leastone of the receiving structure 730 and the anchored structure 1354, toresist longitudinal movement of the fastener (and optionally theanchored structure) with respect to the receiving structure 730. In thismanner, the anchored structure 1354 and/or fastener 100 can be securedin the receiving structure 730 as desired, for any suitable securementtask.

The fastener 100 could include one or more features which assist inperforming a particular securement task. For example, and as shown inFIGS. 16 and 17, a suture lug 1664, configured to retain a suture thread1666, may be provided. In FIGS. 16 and 17, the suture thread 1666 passesthrough a suture aperture 1768 in the suture lug 1664 and thereby thesuture thread may be anchored to a receiving structure 730 whileallowing sliding of the suture thread within the suture aperture 1768.However, it is also contemplated that the suture thread 1666 could berigidly or non-movably connected to the suture lug 1664 in any suitablemanner, if desired.

The sequence of FIGS. 18A-20C depicts the installation of a fastener 100which may be used for a suture anchoring or other task which does notinclude the engagement/connection of an anchored structure (omitted fromthese Figures) with a receiving structure 730 through use of a fastener.The sequence of operation in FIGS. 18A-20C is similar to that describedabove with reference to FIGS. 7A-15B, and similar structures andfunctions to those discussed above will not be specifically discussedagain here.

As seen in FIGS. 18A and 18B, the receiving aperture 1146 includes onlya fastener-receiving portion 1150, and may be formed in any suitablemanner. For most applications of the present invention, the footprint1152 of the receiving aperture 1146 when no anchored structure ispresent will hew rather closely to the fastener perimeter 224. That is,the receiving aperture 1146 in a situation such as that of FIGS. 18A-20Cwill be similar in shape and size to the fastener perimeter 224 suchthat the fastener 100 can be inserted in a desired manner without undueeffort or excessive damage to the receiving structure 730 or thefastener, but so that the teeth 116 will find ample purchase, when thefastener is in in the second alignment, to secure the fastener asdesired.

The receiving aperture 1146 may be formed in any desired manner, andthen, as in FIGS. 19B and 19C, the fastener 100 may be inserted into thereceiving aperture in the first alignment. The fastener 100 may then berotated about the longitudinal axis 104 thereof, in the clockwisedirection of the rotation arrows 1362, into the second alignmentposition shown in FIGS. 20A, 20B, and 20C. FIGS. 20A and 20C show howthe teeth 116 of the fastener 100 have been driven laterally into thereceiving structure 730 to resist pullout and maintain the fastener inthe second alignment for as long as desired.

As can be seen in FIGS. 20A and 20B, rotation of the fastener 100 canleave some empty space within the receiving aperture 1146, laterallyadjacent to the flat faces 120 of the fastener. Optionally, some fillermaterial such as, but not limited to, bone graft, bone cement, or anyother desired material, may be used to fill the receiving aperture 1146and may be helpful in securing the fastener 100 within the receivingaperture. It is also contemplated that the teeth 116, flat faces 120, orany other portion(s) of the fastener shell 106, regardless of useenvironment, could include an ingrowth encouragement feature such as,but not limited to, a coating of natural or artificial bone growthfactor, a texturized (peened or gritted) surface, or any other desiredfeature.

In the above description, the fastener 100 is characterized as beingrotated from the first to the second alignment about the longitudinalaxis 104. While the present invention is agnostic and apathetic as tohow that rotation occurs, it is contemplated that, for most applicationsof the present invention, rotary force will be transmitted from amanipulation tool to the fastener body 102 via a tool-engaging feature114 on the fastener head end 110. Any desired type of tool-engagingfeature 114 and corresponding manipulation tool may be used with thepresent invention, such as, but not limited to, a manipulation toolwhich is an Allen wrench, Philips screwdriver, slotted screwdriver,TORX™ wrench, Robertson wrench, inside hex wrench, or any other suitablemanipulation tool or combination thereof.

As shown in FIGS. 21-22, the fastener 100 of FIGS. 18A-20C has a suturelug 1664 which also can be used as a tool-engaging feature 114 and whichprotrudes from the fastener head end 110. The tool-engaging feature 114of FIGS. 21-22 also includes an anchor feature (the suture aperture1768) which connects to a structure (the suture thread 1666) beinganchored by the fastener 100. In the embodiment of FIGS. 21-22, a lugwrench 2170 includes a lug acceptor 2172 that is configured tosubstantially mate with the suture lug 1664. Rotation of the lug wrench2170 is then transmitted through the lug acceptor 2172 to the suture lug1664 to rotate the fastener 100.

As another example of a suitable means for rotating the fastener, FIGS.23A-23C depict a fastener 100 having a relatively deep center void 2374recessed into the fastener head end 110 and extending into the fastenerbody 102 as a tool-engaging feature 114. The center void 2374 isconfigured to accept at least a portion of a corresponding void wrench2376 in a male-to-female type manner and the center void and void wrenchare configured such that rotation of the void wrench is transmitted tothe fastener body 102 via the center void (i.e., the void wrench doesnot just spin in place within the center void). The arrangement shown inFIGS. 23A-23C is similar in tool-engaging principle to the hex-headtool-engaging feature 114 shown in FIGS. 1-15B. The FIGS. 23A-23Carrangement, however, may be especially desirable when an adsorbable,absorbable, or other “deteriorating” material—which is generally ratherbrittle—is used to make the fastener 100. Since the void wrench 2376 isinserted a relatively long distance into the fastener body 102, the voidwrench can help to strengthen and reinforce the structure of adissolving or absorbable fastener 100 to avoid unwanted damage to thefastener 100 due to the rotation forces.

The undulate or flat quality of a face might not be present in each andevery dimension and portion of that face, but one of ordinary skill inthe art, upon viewing a face of a fastener shell 106, will be able toreadily determine whether the face is undulate or flat, for the purposesof the present invention. Additionally, the boundaries or bordersbetween laterally adjacent faces might not be clearly drawn ordelineated in all embodiments of the present invention, but, again, oneof ordinary skill in the art will be able to at least broadly identifyand differentiate portions of the fastener shell 106 that are undulateor flat.

While the undulate faces 118 and flat faces 120 discussed herein allhave relatively large and similar lateral widths (i.e., the dimensionsof each that combine to form the fastener perimeter 224), it iscontemplated that the undulate faces and flat faces could have anydesired width, down to and including a near-zero width. In other words,the profile 322 may be formed as a quasi-linear construct as alongitudinally extending edge of the fastener shell 106 at a lateralintersection of two flat faces 120.

The pilot hole 728 and/or receiving aperture 1146 may each be created inany desired manner, using any desired manual, automatic, and/orsemi-automatic material removal/shaping tools. Optionally, the receivingaperture 1146 may be formed directly in the receiving structure 730,with no pilot hole 728 previously provided.

The shaping tool 832 could use any suitable structures for placement andguiding of the guided chisel 838 with respect to the guiding rod 834.For example, the “male” and “female” portions of the interlockingfeatures of the guiding rod 834 and guided chisel 838 could be reversedfrom that shown in the Figures. Any other desired (non-dovetail)relatively shaped structures, whether or not interlocking matingactually occurs, could be used for placement and guiding of the guidedchisel 838 with respect to the guiding rod 834.

It is contemplated that movement of the fastener 100 from the firstalignment to the second alignment will occur via rotation of thefastener through about ninety degrees, or a quarter-turn, about thelongitudinal axis 104 of the fastener—this rotation will generally beoriented clockwise to comport with mechanical convention. The rotationwill generally be restricted to this quarter-turn movement to provideadequate securement of the fastener 100 while avoiding damage to thereceiving structure 730 and/or anchored structure 1354 due to repeatedor excessive “biting” or penetrating of the teeth 116 thereinto andpossible overall weakening of the connected structures. However, in aparticular application of the present invention, it may be desirable forthe fastener 100 to be rotated further than ninety degrees, includingone or more full three hundred sixty degree rotations, during actuationof the fastener from the first alignment into the second alignment, andone of ordinary skill in the art can readily provide a suitably designedfastener, receiving structure 730, and/or anchored structure 1354 forsuch a use environment.

To remove the fastener 100 if/when it is no longer desired to be in thesecond alignment in the receiving structure 730, the fastener could becaused to rotate back from the second alignment to the first alignment,such as by a rotation of about ninety degrees about the longitudinalaxis 104 in the opposite direction (e.g., counterclockwise) from theinstallation rotation direction. Any suitable tool, including theinstallation tool, could be used for removal. The fastener 100 can thenbe pulled longitudinally out of the receiving aperture 1146, optionallywith the aid of a removal tool that includes any suitable graspingfeature to aid in pulling the fastener from the receiving structure 730.As another option, the fastener 100 could be rotated further than ninetydegrees, including one or more full three hundred sixty degreerotations, to “back out” of the receiving aperture 1146 similarly toremoval of a standard cylindrical screw/bolt.

While aspects of the present invention have been particularly shown anddescribed with reference to the preferred embodiment above, it will beunderstood by those of ordinary skill in the art that various additionalembodiments may be contemplated without departing from the spirit andscope of the present invention. For example, the specific methodsdescribed above for using the fastener 100 are merely illustrative; oneof ordinary skill in the art could readily determine any number oftools, sequences of steps, or other means/options for placing theabove-described apparatus, or components thereof, into positionssubstantively similar to those shown and described herein. Any of thedescribed structures and components could be integrally formed as asingle unitary or monolithic piece or made up of separatesub-components, with either of these formations involving any suitablestock or bespoke components and/or any suitable material or combinationsof materials; however, the chosen material(s) for the fastener 100should be biocompatible for many applications of the present inventionand may be adsorbable or absorbable to deteriorate or ingrow with thereceiving structure 730 over time. The mating relationships formedbetween the described structures need not keep the entirety of each ofthe “mating” surfaces in direct contact with each other but couldinclude spacers or holdaways for partial direct contact, a liner orother intermediate member for indirect contact, or could even beapproximated with intervening space remaining therebetween and nocontact. Some degree of lateral translation movement may also occurduring rotation of the fastener 100 about the longitudinal axis 104. Therotation of the fastener 100 about the longitudinal axis 104 could occurin the clockwise direction of the rotation arrows 1362 or in acounterclockwise direction, contrary to the rotation arrows. Thefastener body 102 may include a longitudinally-oriented central bore(not shown) through an entire length thereof. Though certain componentsdescribed herein are shown as having specific geometric shapes, allstructures of the present invention may have any suitable shapes, sizes,configurations, relative relationships, cross-sectional areas, or anyother physical characteristics as desirable for a particular applicationof the present invention. Any structures or features described withreference to one embodiment or configuration of the present inventioncould be provided, singly or in combination with other structures orfeatures, to any other embodiment or configuration, as it would beimpractical to describe each of the embodiments and configurationsdiscussed herein as having all of the options discussed with respect toall of the other embodiments and configurations. A device or methodincorporating any of these features should be understood to fall underthe scope of the present invention as determined based upon the claimsbelow and any equivalents thereof.

Other aspects, objects, and advantages of the present invention can beobtained from a study of the drawings, the disclosure, and the appendedclaims.

Having described the invention, we claim:
 1. A fastener, comprising: anelongate fastener body defining a longitudinal axis substantiallycentral thereto, the fastener body having a continuous outer fastenershell laterally surrounding the longitudinal axis, the fastener shelllongitudinally separating a fastener head end and a fastener tip end; atool-engaging feature on the fastener head end; and a plurality of teethlocated on the fastener shell and extending substantially laterallyoutward from the longitudinally axis; wherein the fastener shell iscomprised of at least one undulate face and at least one substantiallyflat face, the plurality of teeth being located only on the undulatefaces, each tooth being longitudinally separated from adjacent teethalong an undulate face.
 2. The fastener of claim 1, wherein each toothof a selected undulate face includes a leading edge apex defined by aconcave feature in a laterally oriented profile of the selected undulateface, the leading edge apex causing the tooth to be asymmetrical alongthe laterally oriented profile, the leading edge apex being located on aportion of the selected undulate face that leads engagement of the toothwith an ambient material when the fastener is being rotated about thelongitudinal axis.
 3. The fastener of claim 1, wherein each tooth of asecond undulate face, other than the selected undulate face, issymmetrical along a laterally oriented profile of the second undulateface.
 4. The fastener of claim 1, wherein the tool-engaging feature is atool-accepting void recessed into the fastener head end.
 5. The fastenerof claim 1, wherein the tool-engaging feature is a tool-engaging lugprotruding from the fastener head end.
 6. The fastener of claim 5,wherein the tool-engaging lug includes an anchor feature connected to astructure being anchored by the fastener.
 7. The fastener of claim 1,wherein the fastener shell is comprised of at least two undulate faces,each undulate face being laterally separated from the other undulatefaces around a laterally-oriented perimeter of the fastener shell by aflat face.
 8. The fastener of claim 1, wherein at least a portion of thefastener shell includes an ingrowth encouragement feature.
 9. Afastening method for substantially securing an inserted structure withina receiving structure, the fastening method comprising: inserting atleast a portion of the fastener of claim 1 into a receiving aperture ofthe receiving structure; inserting at least a portion of the insertedstructure into the receiving aperture, laterally adjacent to thefastener; rotating the fastener substantially a quarter turn about alongitudinal axis thereof; penetrating at least one tooth of thefastener laterally into a wall of the receiving aperture; andconcurrently with penetration of the at least one tooth into the wall ofthe receiving aperture, penetrating at least one other tooth of thefastener laterally into the inserted structure.
 10. The fastening methodof claim 9, wherein the inserted structure includes a bone block and thereceiving structure is a graft tunnel.
 11. A method of installing afastener into a receiving structure, the method comprising the steps of:providing a fastener, the fastener including: an elongate fastener body,having longitudinally spaced fastener head and fastener tip ends, thefastener body defining a longitudinal axis, two elongate flat faces,each flat face extending substantially parallel to, and laterally spacedfrom, the longitudinal axis, the two flat faces being located laterallyopposite one another on the fastener body, and two elongate undulatefaces, each undulate face having a plurality of longitudinally spacedteeth arranged thereupon, each undulate face extending substantiallyparallel to, and laterally spaced from, the longitudinal axis, the twoundulate faces being located laterally opposite one another on thefastener body, and the two undulate faces being laterally separated fromone another by interposed flat faces, wherein a fastener perimeter isdefined in a lateral plane by the two flat faces and the two undulatefaces, the fastener perimeter entirely laterally surrounding thelongitudinal axis; providing a longitudinally oriented receivingaperture in the receiving structure; inserting the fastener tip end intothe receiving aperture; penetrating the receiving aperture with thefastener body to a predetermined depth; maintaining the fastener in thereceiving aperture in a first alignment; rotating the fastener about thelongitudinal axis within the receiving aperture into a second alignment;driving at least one tooth laterally into the receiving structure fromthe receiving aperture due to rotation of the fastener into the secondalignment; and with the at least one tooth driven laterally into thesubstrate, maintaining the fastener in the receiving aperture in thesecond alignment to resist longitudinal movement of the fastener withrespect to the receiving aperture.
 12. The method of claim 11, whereinthe step of rotating the fastener about the longitudinal axis within thereceiving aperture into a second alignment includes the step of rotatingthe fastener substantially ninety degrees about the longitudinal axiswithin the receiving aperture into the second alignment.
 13. The methodof claim 11, including the steps of: providing an anchored structurewithin the receiving aperture, laterally adjacent to the fastener in thefirst alignment; and driving at least one tooth laterally into theanchored structure due to rotation of the fastener into the secondalignment, the at least one tooth driven laterally into the anchoredstructure being arranged upon a different undulate face than the atleast one tooth driven laterally into the receiving structure.
 14. Themethod of claim 13, wherein the step of providing an anchored structurewithin the receiving aperture includes the steps of: providing a boneblock, the bone block dimensioned for insertion into the receivingaperture; providing an elongate graft ligament having first and secondgraft ends; directly connecting the first graft end to the bone block;and inserting at least a portion of the bone block, as an anchoredstructure, into the receiving aperture.
 15. The method of claim 11,wherein the step of providing a longitudinally oriented receivingaperture in the receiving structure includes the step of providing arotationally asymmetrical receiving aperture in the receiving structure,the rotationally asymmetrical receiving aperture having astructure-receiving portion laterally adjacent to a fastener-receivingportion.
 16. The method of claim 11, wherein the step of providing arotationally asymmetrical receiving aperture in the receiving structureincludes the steps of: drilling a substantially cylindrical receivingaperture in the receiving structure; inserting at least a portion of anelongate guiding rod longitudinally into the cylindrical receivingaperture; mating a guided chisel with the guiding rod when the guidingrod is at least partially located in the cylindrical receiving aperture;guiding the guided chisel into the receiving structure laterallyadjacent to the cylindrical receiving aperture through slidingengagement between the guided chisel and the guiding rod; and excavatingthe receiving structure laterally adjacent to the cylindrical receivingaperture to create the rotationally asymmetrical receiving aperture. 17.The method of claim 11, including the steps of: providing each tooth ofa selected undulate face with a leading edge apex defined by a concavefeature in a laterally oriented profile of the selected undulate face;and locating the leading edge apex on a portion of the selected undulateface that leads engagement of the tooth with an ambient material whenthe fastener is being rotated about the longitudinal axis.
 18. Themethod of claim 11, including the step of transmitting rotary force froma manipulation tool to the fastener body via a tool-engaging feature onthe fastener head end.
 19. A fastener, comprising: an elongate fastenerbody, having longitudinally spaced fastener head and fastener tip ends,the fastener body defining a longitudinal axis; two elongate flat faces,each flat face extending substantially parallel to, and laterally spacedfrom, the longitudinal axis, the two flat faces being located laterallyopposite one another on the fastener body; and two elongate undulatefaces, each undulate face having a plurality of longitudinally spacedteeth arranged thereupon, each undulate face extending substantiallyparallel to, and laterally spaced from, the longitudinal axis, the twoundulate faces being located laterally opposite one another on thefastener body, and the two undulate faces being laterally separated fromone another by interposed flat faces; wherein a fastener perimeter isdefined in a lateral plane by the two flat faces and the two undulatefaces, the fastener perimeter entirely laterally surrounding thelongitudinal axis.
 20. The fastener of claim 19, wherein each tooth of aselected undulate face includes a leading edge apex defined by a concavefeature in a laterally oriented profile of the selected undulate face,the leading edge apex being located on a portion of the selectedundulate face that leads engagement of the tooth with an ambientmaterial when the fastener is being rotated about the longitudinal axis.21. The fastener of claim 19, wherein the fastener head end includes atool-engaging feature configured to transmit rotary force from amanipulation tool to the fastener body.
 22. The fastener of claim 19,wherein the fastener has a smaller lateral footprint size at thefastener tip end than a corresponding lateral footprint of the fastenerat the fastener head end.